System and method for connecting parts

ABSTRACT

A system and method for connecting dissimilar materials is described. In one embodiment, the system may be used to produce a break apart frame that includes a first section and a second part which is disengagably connected to the first part by fastening members. The first part includes a head tube, a top tube and a down tube. The second section includes a bottom bracket, a seat tube, a pair of seat stays and a pair of chain stays. A connection tube extends from the bottom bracket so as to be disengagably connected to the down tube. An end tube is connected to the seat tube and disengagably connected to the seat tube.

RELATED APPLICATION/PRIORITY CLAIM

This application claims priority under 35 USC 120 and is a continuationin part of U.S. patent application Ser. No. 11/093,624 filed on Mar. 29,2005 entitled “System and Method for Connecting Parts” which claimspriority under 35 USC 120 and is a continuation of U.S. patentapplication Ser. No. 10/256,637 filed on Sep. 27, 2002 and entitled“System and Method for Connecting Parts” which is turn claims priorityfrom U.S. Provisional Application Ser. No. 60/326,173 filed on Sep. 28,2001, all of which are incorporated herein in its entirety.

BACKGROUND OF THE INVENTION

This invention relates generally to a system and method for connectingmaterials that are typically difficult to connect together, andparticularly to assembling sections of a bicycle frame that can bedisassembled for convenient transport and storage.

In typical applications where it is desirable to connect two differentmaterials together, it is often not attempted due to the problemsensuring a good connection. In one example, a bicycle frame may have oneor more different pieces that are made of different materials, such asmetal parts that need to be connected to carbon fiber parts. Typically,it is necessary to bond the carbon fiber parts to the metal partalthough the bonding process is not very strong and tends to break. Thebonding process is also susceptible to corrosion and requires thebuilder to have specialized skills and equipment. Thus, the typicalbonding process has undesirable drawbacks including a weak connectionbetween the two different parts that is susceptible to breakage. Thus,it is desirable to provide a system for connecting parts of twodifferent materials, such as different parts of a bicycle frame, and itis to this end that the present invention is directed.

FIG. 14 shows a conventional bicycle 1 which generally includes a frontwheel 2, pedals 4, a rear derailleur 6 for moving a chain 5 over asprocket cassette 7 attached to a rear wheel 3, and hand brakes 9attached to handlebars 10. These components are in fixed positionsrelative to one another and to a triangular bicycle frame that includesa top tube 12, a down tube 13, and a seat tube 16. The seat tube 16, thedown tube 13, and the pedal assembly 4 meet at a bottom bracket shellthat is not shown in the figure. The “pedal assembly,” as used herein,includes a crank, pedals, and various peripheral components that makethe pedals function properly. Also extending from the bottom bracket isa pair of chain stays 15 a. The chain stays 15 a, of which only one isshown, connect the pedal assembly to the hub of the rear wheel 3 on bothsides of the rear wheel 3. A pair of seat stays 150 connect the hub ofthe rear wheel 3 to the top of the seat tube 16 on both sides of therear wheel 3. The chain stays 15 and the seat stays 150 connect at thehub of the rear wheel 3 so as to form a V-shape on either side of thebicycle 1. The angled portion of the V-shaped chain stay 15 is attachedto an area near the hub of the rear wheel 3 and the two ends connect tothe hidden bottom bracket and the seat tube 16, respectively. The seattube 16 supports the bicycle seat 18 by holding up the seat post 17.

A rider uses the handlebars 9 to steer the bicycle in the desireddirection. Located near the handlebars 9 are hand brakes 8 and gearshifter 10. The hand brakes 8 are coupled to the brakes by a rear wheelbrake cable 112 a and a front wheel brake cable 112 b. Similarly, thegear shifter 10 shifts gears by activating the rear derailleur 6 and aderailleur 19 to which it is connected by two respective derailleurcables. Only part of the derailleur cables are shown as derailleur cable113 in order to avoid cluttering the figure.

The triangular bicycle frame is typically a one-piece member so that itoccupies a large space and is inconvenient to be carried and stored. Theone-piece frame also increases the space required to store the frame andincurs airline cargo charges. A bicycle frame that is easy to store andtransport while being at least as sturdy and reliable as the one-piecebicycle is necessary.

SUMMARY OF THE INVENTION

The invention provides a system and method for connecting two dissimilarmaterials together in a unique manner. In some embodiments, the systemmay be used to connect portions of a multi-piece bicycle frame asdescribed below. The invention can also be used to connect various otherpieces of dissimilar materials together.

In accordance with one aspect of the present invention, there isprovided a break apart frame which comprises a first section and asecond section which is disengagably connected to the first section byfastening devices or connecting members. The first section includes ahead tube with a top tube and a down tube extending therefrom and an endtube that is connected to a distal end of the top tube. The secondsection includes a bottom bracket with a seat tube extending therefromthat is disengagably connected of the end tube. A connection tubeextends from the bottom bracket so as to be disengagably connected tothe down tube. A pair of chain stays are connected to the bottombracket. In some frames, the two different portions are made ofdifferent materials, such as a metal alloy first portion and a carbonkevlar fiber second portion. The present invention provides a breakapart bicycle frame that can be disassembled into two sections forconvenient storage and transportation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a first bicycle frame section of an exemplary multi-piecebicycle in accordance with the invention;

FIG. 2 depicts a second bicycle frame section that is assembled with thefirst bicycle frame section of FIG. 1;

FIG. 3 depicts a manner in which the first bicycle frame section of FIG.1 and the second bicycle frame section of FIG. 2 are assembled;

FIG. 4A depicts an exemplary clamp that may be used to connect two partsin accordance with the invention;

FIG. 4B depicts how the clamp of FIG. 4A may be used to connect twoparts;

FIG. 5A depicts an alternative clamp that may be used to connect twoparts in accordance with the invention;

FIG. 5B depicts how the clamp of FIG. 5A may be used to connect twoparts;

FIG. 6A depicts yet another alternative clamp that may be used toconnect two parts in accordance with the invention;

FIG. 6B depicts how the clamp of FIG. 6A fits around annular lips;

FIG. 6C depicts how the clamp of FIG. 6A may be used to connect twoparts;

FIG. 7A depicts the parts that may be connected by the clamp of FIG. 4Aor the clamp of FIG. 5A;

FIG. 7B depicts a cross sectional view of a junction connected with theclamp of FIG. 4A or FIG. 5A;

FIGS. 8A-8D depict a cable connector in accordance with the invention;

FIG. 8E depicts how the cable connector of FIGS. 8A-8D is positionedupon assemblage;

FIGS. 9A-9B depict a manner in which two tubes can be connected inaccordance with the invention;

FIG. 10 depicts an alternative multi-piece bicycle frame;

FIG. 11 depicts a third alternative multi-piece bicycle frame;

FIGS. 12A and 12B depict a fourth alternative multi-piece bicycle frame;

FIG. 13 depicts a fifth alternative multi-piece bicycle frame;

FIG. 14 depicts a one-piece bicycle; and

FIGS. 15A-C illustrate an example of another embodiment of the junctionof a first frame part and a second frame part connected with the clamp.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

The invention is particularly applicable to a multiple-piece bicycleframe that is assembled according to the invention and it is in thiscontext that the invention will be described. It will be appreciated,however, that the connection system and method in accordance with theinvention has greater utility, such as to being used for connecting anytwo dissimilar materials together.

As used herein, “horizontal” and “horizontally” refer to a direction ina plane parallel to the ground and “vertical” and “vertically” refer toa direction orthogonal to the plane of the ground. Also, “downward” and“down” refer to a direction in which the ground becomes closer, while“upward” and “up” refer to a direction in which the ground becomesfarther away.

FIG. 1 depicts a first bicycle frame section 70 of an exemplarymulti-piece (break apart) bicycle in accordance with the invention. Thefirst bicycle frame section 70 is designed to be assembled with othersections to form a bicycle. The first bicycle frame section 70 comprisesa head tube 11 to which a handlebar (not shown) and a front wheel (notshown) are to be coupled, and a top tube 12 and a down tube 13 extendingfrom the head tube 11 at an angle to each other. Although not clear fromthe figure, top tube 12 typically extends in a substantially horizontaldirection. At the distal end of the top tube 12 is an end tube 50 towhich a seat post 17 is to be connected. The end tube 50 is a hollowtube having a sidewall with a pair of lugs 600. Each of the lugs 600 hasa hole 602, which may be threaded, and the holes are aligned so that ascrew bolt 601 may be inserted through the holes. When the screw bolt601 is threaded into the holes 602, the end tube 50 tightens around theobject that is inserted into the hollow end tube 50, such as the seattube 17. At the distal end of the down tube 13 is a first annular lip131. An annular lip, as used herein, refers to any protruding portion ator near an end of a frame portion, such as a flange.

Extending alongside the top tube 12 is a brake cable 112 thatconstitutes a part of the bicycle's braking mechanism. The brake cable112 extends from the hand brakes that are attached near the handlebars 8(not shown) to a pair of brake pads that act on the rear wheel 3 (seeFIG. 14). The brake cable 112 typically extends substantially parallelto the top tube 12. Extending along the down tube 13 is a derailleurcable 113 that connects the gear shifter 10 (see FIG. 14) located nearthe handlebars to the derailleur located near the rear wheel.

FIG. 2 depicts a second bicycle frame section 72 including a bottombracket shell 14 to which the pedal assembly 4 (see FIG. 14) isattached. Besides the pedal assembly, a pair of chain stays 15 a, a seattube 16, and a connection tube 30 extend from the bottom bracket shell14 in different directions. The chain stays 15 connect the bottombracket shell 14 to the hub of the rear wheel 3, while the seat tube 16extends substantially vertically to be joined with the end tube 50 ofthe first bicycle frame section 70. A pair of seat stays 150 areconnected to the seat tube 16. Like the end tube 50 (see FIG. 1), theseat tube 16 has two lugs 604 connected to the sidewall of the hollowtube 16 so that the seat tube 16 can be tightened around an object(e.g., seat post 17) by screwing a bolt 605 into holes 606. The two lugs604 are separated from each other, for example with a slit (not shown)located between the two lugs and extending part way down the seat tube16. When the screw bolt 605 is screwed into holes 606, the two lugs 600are brought closer to each other, narrowing the slit. The connectiontube 30 extends from the bottom bracket shell 14 toward the down tube 13of the first bicycle frame section 70. The connection tube 30 has asecond annular lip 31 at the distal end. The second annular lip 31 mayhave the same diameter as the first annular lip 131 of the first bicycleframe section 70 so that the two annular lips can be matched up uponassembling. Since the derailleur cable 113 extends along the down tube13 from the hand brakes attached near the handle bars (not shown) to arear wheel (not shown), the derailleur cable 113 needs to be connectedacross the down tube when the first and second bicycle frame sections 70and 72 are assembled. Details on how the cable 113 is assembled areprovided below, in reference to FIGS. 8A-8E.

FIG. 3 depicts how the first bicycle frame section 70 and the secondbicycle frame section 72 are assembled by connecting the two sections ata down tube junction 74 and a seat tube junction 76. At the down tubejunction 74, the first annular lip 131 is connected with the secondannular lip 31 with a clamp 20 shown in FIG. 4A and FIG. 5A below, inthe manner shown in FIGS. 4B and 5B. At the seat tube junction 76, theend tube 50 is connected with the seat tube 16. Preferably, the end tube50 and the seat tube 16 have approximately the same diameter. Since boththe end tube 50 and the seat tube 16 are hollow, the seat post 17 isinserted through the end tube 50 and into the seat tube 16. Once theseat post 17 is inserted to achieve the seat height desired by therider, the end tube 50 and the seat tube 16 are tightened around theseat post 17 by screwing a bolt into the openings of lugs 600 and lugs604. More details about how the end tube 50 and the seat tube 16 areconnected are provided below, in reference to FIGS. 9A and 8B. The rearwheel brake cable 112 and the derailleur cable 113 are omitted in FIG. 3for clarity of illustration on how the first bicycle frame section 70 isassembled with the second bicycle frame section 72. The first bicycleframe section 70 and the second bicycle frame section 72 may be made ofaluminum, aluminum alloy, titanium, carbon fiber, and sometimesmagnesium. The first bicycle frame section 70 and the second bicycleframe section 72 need not be made of the same material.

FIG. 4A depicts an exemplary clamp 20 that may be used for the down tubejunction 74 in accordance with the invention. The clamp 20 joins thefirst annular lip 131 with the second annular lip 31 (see FIG. 4B),thereby securely connecting the down tube 13 with the connection tube 30so that they do not disengage during a ride. The clamp 20 may include anupper arm 40 and a lower arm 42 hinged together by a hinge 44 thatpermits the two arms to pivot with respect to each another. For example,the hinge 44 allows the lower arm 42 to pivot around the hinge 44 in thedirections indicated by arrows 45 a and 45 b. The upper arm 40 may havea semicircular shape with the hinge 44 on one end and a first connectingshoulder 46 on the other. The first connecting shoulder 46 has a hole 47that extends all the way across the connector shoulder 46, and theinside of hole 47 is threaded so that a screw bolt 51 a may be insertedinto it. The lower arm 42 may have a semicircular shape similar to theupper arm 40 with one end connected to the hinge 44 and another endhaving a second connecting shoulder 48. Like the first connectingshoulder 46, the second connecting shoulder 48 has a hole 49 extendingthrough it so that a screw bolt 51 a can be inserted first through thehole 49 and then through the hole 47 as shown by the arrow 51,connecting the first and the second connecting shoulders. When the lowerarm 42 is pivoted around the hinge 44 in the direction of arrow 45 a sothat the two connecting shoulders 46 and 48 are far apart from eachother, the clamp is said to be “opened.” On the other hand, when thelower arm 42 is pivoted in the direction of arrow 45 b so that the twoconnecting shoulders 46 and 48 are close or touching, the clamp is saidto be “closed.” As the screw bolt 51 a is threaded through the holes 49and 47, clamp 20 tightens, bringing the connecting shoulders 46 and 48closer to each other.

Each arm of the clamp 20 may have a groove 56 into which the firstannular lip 131 and the second annular lip 31 may be placed so that theclamp 20 holds the two annular lips securely together. The groove 56 isa recessed portion located on the inside surface of the clamp 20 betweena first sidewall 52 and a second sidewall 54. The width of the groove 56is approximately equal to the combined width of the annular lips 131 and31. The groove 56 may be angled/tapered so that it fits around theannular lips tighter as the annular lips go further into the groove 56.The angled/tapered shape of the groove 56 ensures that as the screw bolt50 is threaded into the holes 49 and 47, the annular lips 31 and 131 areforced into the narrower portion of the groove 56, being pressedtogether tighter. A person of ordinary skill in the art would understandto select a curvature and depth for the groove 56 that best holds theannular lips together.

FIG. 4B depicts how the clamp 20 may be used to connect the firstannular lip 131 and the second annular lip 31. The annular lips 131 and31, which are approximately the same size, are placed in contact witheach other to form a juncture ring having the combined thickness of thefirst annular lip 131 and the second annular lip 31. The clamp is then“opened” so that it can be placed around the first annular lip 131 andthe second annular lip 31. After the groove 56 is positioned over thejunction ring, the clamp is “closed” so that the junction is insertedinto the groove 56. Then, the screw bolt 51 a is used to tighten theclamp 20. In addition, a nut 53 may be threaded onto the bolt andtightened to connect the two annular lips together, thereby joining theconnecting tube 30 with the down tube 13. Any conventional securingmeans other than a screw bolt and a nut may be used.

FIG. 5A depicts an alternative clamp 20 that may be used to join thefirst annular lip 131 with the second annular lip 31. This alternativeclamp 20 is similar to the clamp shown in FIG. 4A in that it includes anupper arm 40 and a lower arm 42 having semicircular shapes. However,unlike the clamp in FIG. 4A, the two arms of the alternative clamp 20are not connected by a hinge. Instead of a hinge, each arm has two lugs,one on each end. The upper arm 40 has a connector shoulder 46 a and aconnector shoulder 46 b, each of which has a threaded hole 47 a and 47b, respectively. Likewise, The lower arm 42 has a lug 48 a and a lug 48b with holes 49 a and 49 b, respectively. A first screw bolt 51 aa maybe inserted through hole 49 a and hole 47 a, and a second screw bolt 51ab may be inserted through hole 49 b and hole 47 b. The upper arm 40 andthe lower arm 42 have a groove 56 in which the first annular lip 131 andthe second annular lip 31 are placed and held together. When the boltsare screwed in, the upper arm and the lower arm come close together,tightening around the down tube 13 and the connection tube 30 andfastening them together. The inside wall of this two-piece clamp 20 hasa groove 56 similar to the inside wall of the one-piece clamp 20 shownin FIG. 4A.

FIG. 5B depicts how alternative clamp 20 may be used to connect thefirst annular lip 131 and the second annular lip 31. The upper arm 40 isplaced above the down tube junction 74, and the lower arm 42 is placedunderneath the down tube junction 74 with the inside walls of each armfacing the junction. Then, the annular lips 131 and 31 are matched andpressed against each other to form a juncture ring that includes acircular interface of the two annular lips. The upper arm 40 ispositioned to fit the upper part of the ring into the groove 56 (notshown), and the lower arm 42 is raised to fit the lower part of the ringinto the groove 56. The screw bolts 50 a and 50 b are then used to holdthe upper arm 40 and the lower arm 42 together, which in turn hold theannular lips together at the down tube junction 74.

FIG. 6A shows yet another alternative embodiment of clamp 20 that may beused to join the first annular lip 131 with the second annular lip 31.The clamp 20 shown in FIG. 6A is substantially similar to the clamp 20shown in FIG. 4A except for teeth 57 in the groove 56. The groove 56,instead of being a continuous receded portion along the inner peripheryof the clamp 20, includes substantially flat portions 57 a and recededportions 57 b that are arranged in an alternating manner. This type ofclamp 20 with teeth 57 is useful for modified versions of annular lips31 and 131 that also have teeth. The receded portions 57 b of the groove56 may be angled/tapered like the continuous groove 56 in FIG. 4A sothat each of the teeth gets “sharper” as it gets closer to the end.

FIG. 6B depicts how the teeth 57 of clamp 20 fit around annular lips 31and 131. In order for a clamp 20 that has teeth to be used, the annularlips 31 and 131 must also have teeth 32 including flat portions 32 a andprotruding portions 32 b. Each of the protruding portions 32 b is shapedand sized to fit into the receding portion 57 b and the flat portions 32a are designed so that when the protruding portions 32 b are insertedinto the receding portions 57 b, the flat portions 32 a come in contactwith the flat portions 57 a. A person of ordinary skill in the art wouldunderstand how to design the teeth 57 on the clamp 20 to provide asecure interlocking seal between the annular lips 31 and 131 that haveteeth 32.

FIG. 6C depicts how the clamp 20 of FIG. 6A is used to connect the firstannular lip 131 and the second annular lip 31. The upper arm 40 isplaced above the down tube junction 74, and the lower arm 42 is placedunderneath the down tube junction 74 with the inside walls of each armfacing the junction. Then, the flat portions 32 a and the protrudingportions 32 b of the annular lips 131 and 31 are matched and pressedagainst each other to form a juncture ring that includes an interface ofthe two annular lips. The upper arm 40 is positioned to fit theprotruding portions 32 b of the upper half of the juncture ring into thereceding portions 57 b (not shown), and the lower arm 42 is raised tofit the protruding portions 32 b of the lower half of the juncture ringinto the receding portions 57 b. The screw bolts 51 aa and 51 ab arethen used to hold the upper arm 40 and the lower arm 42 together, whichin turn hold the annular lips together at the down tube junction 74.

The clamp 20 may be made of investment cast steel, stainless steel, orany other material of sufficient strength. Optionally, the clamp may becoated to prevent rusting, for example with nickel. A person of ordinaryskill in the art would understand that the material of which the clamp20 is made should be determined based on the types of material thebicycle frames are made. Similarly, the dimensions of the clamp 20 areadapted to the dimensions of the bicycle frames.

FIG. 7A depicts the connection tube 30 and the down tube 13 at the downtube junction 74. Both the connection tube 30 and the down tube 13 haveannular lips 31 and 131, respectively, of substantially the samediameter. In some embodiments, one of the tubes to be connected (e.g.,the down tube 13 in the figure) has an inner lip 132. The inner lip 132has an outer diameter that is smaller than the inner diameter of theconnecting tube 30 by just enough so that when the two annular lips arematched and pressed against each other, the inner lip 132 is insertedinto the connection tube 30. The surface of the down tube 13 curves upto form a slope 133 that becomes the first annular lip 131. Similarly,the surface of the first annular lip 131 curves toward the inside of thetube to form a curve 134 which turns into the inner lip 132. Thediameter of the inner lip 132 is smaller than the diameter of the downtube 13, and the diameter of the down tube 13 is smaller than thediameter of the first annular lip 131. As for the connection tube 30,the outer surface of the connection tube 30 curves outward to form aslope 33 which eventually becomes the second annular lip 31 having alarger diameter than the connection tube 30. The second annular lip 31then curves down first toward the center of the tube and then toward theinner wall of the tube, forming an edge 34 (see FIG. 7B). The structuresof the connection tube 30 and the down tube 13 at the down tube junction74 are interchangeable, as long as one of the tubes has the inner lip132 and the other tube does not.

FIG. 7B depicts a cross sectional view of the down tube junction 74sliced along the length of the tube after the clamp 20 has beentightened. This cross sectional view illustrates how the first annularlip 131, the inner lip 132, and the second annular lip 31 combine at thedown tube junction 74. The first annular lip 131 and the inner lip 132form the curve 134, and this curve 134 fits with the edge 34 of theconnection tube 30 to form a curved interface 36, as shown. The firstannular lip 131 and the second annular lip 31 are pressed against eachother by the sidewalls 52 and 54 of the clamp 20. When the clamp 20 isplaced over the annular lips 131, 31, the annular lips 131, 31 fit intothe groove 56 and prevent the down tube 13 and the connection tube 30from moving in along the y-direction as shown by an arrow 39. Thepresence of the inner lip 132 strengthens the structural integrity ofthe down tube junction 74 by providing extra support in the radialdirection, and contributes to maintaining the second annular lip 31matched with the first annular lip 131. More specifically, once thefirst annular lip 131 and the second annular lip 31 are placed insidethe groove 56, the sidewalls 52 and 54 (see FIG. 4A) apply a force inboth directions along the y-direction, pushing the annular lips intoeach other. When the clamp 20 is tightened, it applies onto the annularlips 131 and 31 a force directed radially inward (toward the center ofthe tube), and the inner lip 36 helps counter this inward radial forceby “pushing” the annular lips into the groove 56, radially outward. They-directional forces applied by the sidewalls 52 and 54, the radiallyinward force applied by the surface of the groove 56 that connects thesidewalls 52 and 54, and the radially outward force applied by the innerlip 132 together keep the annular rings 131 and 31 securely “locked.”Hence, any sliding between the first annular lip 131 and the secondannular lip 31 at the interface 36 is minimized. The down tube 13 andthe connection tube 30 are typically hollow to reduce the weight of thebicycle. Since the annular lips are “locked” together by the clamp 20,the down tube 13 and the connection tube 31 cannot be separated without“opening” the clamp 20.

FIG. 8A depicts a cable connector 120 that is used to join a firstportion cable 113 a with the second portion cable 113 b across the downtube junction 74 to form the derailleur cable 113 in accordance with theinvention. The cable connector 120 includes a male connector 122 thatscrews into a female connector 124. The male connector 122 is a screwwith a tunnel 123 that extends through the center of the head. The firstportion cable 113 a is inserted into the hole 123 and terminates with astandard end. As this standard end is thicker than the rest of thederailleur cable 113, the end does not get pulled out through the hole123 and the first portion 113 a of the cable remains connected to themale connector 122. The female connector 124 includes a threaded cavity125 connected to a solid section 126. The threaded cavity 125 isdesigned to accommodate the male connector 122. Like the male connector122, the solid section 126 has a tunnel that extends from an end of thefemale connector 124 to the threaded cavity 125. The second portioncable 113 b is inserted through this tunnel. Then, a bolt 128 is screwedinto the tunnel in the direction of the plane of the page, in adirection orthogonal to the direction in which the tunnel extends. Thebolt 128 may be, for example, an allen key bolt or a set screw. As thebolt 128 is screwed in, it comes in contact with the second portioncable 113 b that lies in the tunnel, and eventually presses the secondportion cable 113 b against an inner wall of the tunnel. By pressing thecable hard against the inner wall of the tunnel, the bolt 128 preventsthe cable from sliding in and out of the tunnel, effectively keeping itfixed to the female connector 124.

The bolt 128 is inserted through openings located on a platform 129,which is raised above the rest of the outer surface of the femaleconnector 124. The platform 129 is raised to accommodate the bolt 128,which needs to have a predetermined minimum length in order toeffectively hold the second portion cable 113 b in place. Without theplatform 129, the bolt 128 could only be as long as the distance betweenthe surface of the female connector 124 and the wall of the tunnel thatruns through it. If this distance is too short, the bolt 128 would betoo short and could crack under strain during a ride. Since the firstportion cable 113 a is fixed to the male connector 122 and the secondportion cable 113 b is connected to the female connector 124, the twocable portions are connected to form a derailleur cable 113 when themale connector is screwed into the threaded cavity 125 of the femaleconnector 124.

FIG. 8B depicts an alternative embodiment of the cable connector 120.This cable connector 120 is substantially similar to the cable connectorshown in FIG. 8A, except that the overall size is larger and there is anextra bolt 128 on the platform 129. The invention is not limited tobeing implemented with a cable connector of a certain size or shape, andmay be any two parts that can be disengagably yet securely fixed to eachother wherein one part is securely connected to a first portion of thecable and the other part is securely connected to a second portion ofthe cable that is to be connected with the first portion of the cable.In some embodiments, the smaller cable connector of FIG. 8A is used forconnecting the derailleur cable 113 and the larger cable connector ofFIG. 8B is used for connecting the brake cable 112. Since brake cablestend to be thicker than the derailleur cables, a larger cable connectormay be suitable for a brake cable that takes more force to be fixed inplace and a smaller cable connector may be suitable for a derailleurcable.

FIGS. 8C and 8D are isometric views of the female connector 124 of FIG.8A shown from different angles. The isometric views show that the end127 has an opening 127 a into which the cable is inserted. The isometricview also shows that there is a flat portion 130 on the surface of thefemale connector 124 that is farthest away from the platform 129. When acable is connected with the cable connector 120, the cable connector 120is automatically positioned close to a portion of the frame such as thedown tube 13 or the top tube 12, and rattles during the ride as twocylindrical objects vibrate against each other. The flat portion 130 isdesigned to reduce this rattling that is probably annoying to the rider.As shown in FIG. 8E, the flat portion 130 is positioned so that it isclose to the nearby top tube 12. The flat portion 130 is shaped so thatthe rattling caused by the connection tube 120 “hitting” the top tube 12is minimized without affecting the security with which the cable isfixed to the inside of the female connector 124.

FIG. 9A depicts the seat tube junction 76 where the end tube 50 meetsthe seat tube 16. The end tube 50 and the seat tube 16, which preferablyhave the same diameter, are designed to be connected with the seat post17, only a part of which is shown in FIG. 9A. The end tube 50 is weldedon to the top tube 12 and integrated into the first bicycle framesection 70 (see FIG. 3) before the end tube 50 is connected with theseat tube 16. Likewise, the pair of seat stays 150 are welded on to theseat tube 16 and integrated into the second bicycle frame section 72(see FIG. 2) before the seat tube 16 is connected to the end tube 50.The seat post 17 is designed to fit snugly through the end tube 50 andinto the seat tube 16 from the top. Once the seat post 17 is inserted tothe desired seat height, the lugs 600 and the lugs 604 are tightenedaround the seat post 17 so that the end tube 50 and the seat tube 16 arefixed in position. Connected to the seat tube 16 is a cable holder 164designed to hold the cable 112 that extends across most of the length ofthe top tube 12. More details about the cable holder 164 is providedbelow, in reference to FIG. 9B.

FIG. 9B depicts the seat tube junction 76 from a different angle thanFIG. 9A, and omits seat post 17. FIG. 9B shows an exemplary embodimentof the cable holder 164 that includes a tubular structure 165 with aslit 166 along a sidewall so that the brake cable 112 can easily beplaced into and taken out of the tubular structure 165. The brake cable112 extends along the top tube 12, passes through the tubular structure165, and then bends downward toward the rear wheel 3 (see FIG. 14). Thetubular structure 165 is positioned to guide the brake cable 112 in adesired direction. Without the cable holder 164, the rear brake cable112 would not travel substantially parallel to the top tube 12, butwould slant down toward the brake pads, possibly being a nuisance to therider as he pedals. The cable holder 164 keeps the leg area clear ofcables.

The lower end 500 of the end tube 50 is cut at an angle, and the upperend 160 of the seat tube 16 is also cut at an angle to match the lowerend 500 of the end tube 50. The angle of the lower end 500 and the angleof the upper end 160 are designed so that the end tube 50 and the seattube 16 combine to form one long tube only when the end tube 50 and theseat tube 16 are positioned in a particular way relative to each other.For example, in the embodiment shown in FIG. 9B, the end tube 50 and theseat tube 16 fit together only when the top tube 12 is aligned with thespace between the two lugs 604 attached to the seat tube 16. Therefore,when the end tube 50 and the seat tube 16 are properly placed to form asingle tube, the two tubes do not rotate around an axis 162 through thecenter of the tube. Furthermore, the tube that results as a combinationof the seat tube 16 and the end tube 50 is not perfectly vertical, butslightly slanted backwards (see FIG. 14) in order to comfortablyaccommodate the rider who leans forward to steer the bicycle. Thus, ifthe interface between the end tube 50 and the seat tube 16 lies in aplane that is orthogonal to the axis 162, the interface does not lie ina plane that is perpendicular to the direction of the gravity. As aresult, the gravity applies a force in the plane of the interface,causing a great strain on the seat tube junction 76. Due to this strain,the seat tube 16 will “want” to slide forward and the end tube 50 will“want” to fall behind the seat tube 16, possibly causing an injury tothe rider. This risk of injury is greatly reduced by cutting the lowerend 500 of the end tube 50 and the upper end 160 of the seat tube 16 atan angle to the axis 162. By placing the interface in a plane that isnot perpendicular to the axis 162, the interface can be positionedsubstantially perpendicular to the force of gravity. Thus, any forceapplied in the plane of the interface is minimized, and the strain atthe seat tube junction 76 is greatly reduced.

The end tube 50 and at least the top portion of the seat tube 16 that isshown in FIGS. 9A and 8B may be made of any material that a person ofordinary skill in the art deems suitable. The material depends on thetype of material the bicycle frame is made of. For example, if the toptube 12 and the down tube 13 are made of aluminum, the end tube 50 andthe portion of the seat tube 16 near the seat tube junction 76 arepreferably also made of aluminum.

FIG. 10 depicts a bicycle frame 10 that includes the first bicycle framesection 70 and the second bicycle frame section 72 connected at the downtube junction 74 and the seat tube junction 76. Using the connectionmethod in accordance with the invention, the two pieces of the frame areconnected together in a secure manner. More specifically, the down tubejunction 74 is secured with a clamp 20 in the manner described above inreference to FIG. 4B, FIG. 5B, and FIG. 7. The seat tube junction 76 issecured by tightening the lugs 500 and the lugs 604 around the seat post17 as tightly as possible, in the manner described above in reference toFIG. 9A and FIG. 9B. These connection methods are especiallyadvantageous in that they establish a secure connection even if theportions of the frame that are connected together are of dissimilarmaterials. Furthermore, these connection methods provide an easilyreversible connection. The connection tube 30 and the down tube 13 canbe separated by opening the clamp 20, and the end tube 50 and the seattube 16 are separated by loosening the lugs 600 and 605 and sliding outthe seat post 17.

FIG. 11 is a diagram illustrating another example of a multi-piecebicycle frame 80 being connected together using the clamp 20 and anothercomponent. As this bicycle frame 80 has similar components to the frameas shown in FIG. 10 that have like reference numerals, those componentswill not be described here. In this embodiment, a first portion 82 thatincludes the head lug 11, the top tube 12 and the down tube 13 isconnected to a second portion 84 that includes the seat tube 16, thechain stays 15 (only one is shown), and the seat stays 150 (only one isshown). At an upper end, the first portion 82 may include a hollow tube90 that includes a pair of lugs 92. The lugs 92, which are similar tothe lugs 600 and lugs 604 depicted in FIG. 9A, are separated by a gapbetween the two lugs 92 that can be narrowed with a bolt (not shown)inserted into the holes 93. The second portion 84 comprises a smallertube 94 having a slot 96 on its side. When the first portion 82 iscoupled with the second portion 84, the hollow tube 90 of the firstportion slides over the smaller tube 94. The smaller tube 94, which isalso hollow, accommodate a seat post. Once the hollow tube 90 is slidover the smaller tube 96 and the seat post is inserted into the smallertube 96, the lugs 92 are tightened. When the lugs 92 are tightened, aradially inward pressure is applied to the smaller tube 94 and the slit96 is narrowed. Thus, by tightening the lugs 92, the smaller tube 94,the seat post that is inserted into the smaller tube 94, and the hollowtube 90 are is fixed in place. In this manner, the multi-piece bicycleframe is connected together using the connecting system in accordancewith the invention.

In this embodiment, the first portion 82, known as a front triangle, mayhave one or more different custom sizes and may be made out of an alloyof steel and titanium. The second portion 84, known as a rear triangle,may have one or more different sizes and may be made out of carbonkevlar fiber material. In this embodiment, the two portions areconstructed of different materials since the two portions have desirabledifferent properties (e.g., the front portion needs to be strong toabsorb shock and force while the rear portion can be lightweight toreduce the weight of the frame) so that the two portions are desirableconnected together using the connecting system in accordance with theinvention. Thus, in accordance with the invention, the multi-piece framemay include a clamp that connects a lower end of the first and seconddissimilar material portions at a junction 88.

FIGS. 12A and 12B illustrate another embodiment of the multi-piecebicycle frame being connected together using a clamp similar to theclamp 20 of FIG. 5A and another component. A protrusion 25 and a lug 22are respectively connected to two ends of one of the two parts 20. Theother part 20 has a slot 27 defined in one end thereof and a lug 22 onthe other end thereof. The protrusion 25 is received in the slot 27 andconnected with each other by a bolt 28. Another bolt extends through thetwo aligned lugs 22. The two ring-shaped lugs 600 are cooperated with aquick-release device to secure the seat post 17 and the end tube 50.

FIG. 13 illustrates yet another embodiment of the multi-piece bicycleframe 10 being connected together using the connecting clamp and anothercomponent. In particular, FIG. 13 shows that only one quick-releasedevice 60 that is connected to the end tube 50 and an insertion 161 isconnected to the seat tube 16. The quick release device 60 comprises ahandle that tightens a tube around another smaller tube to hold the twotubes together. In more detail, the insertion 161 and the seat post 17are then secured in the end tube 50 by the quick-release device 60. Thetwo parts of the frame are designed so that when the end tube 50 fitsover the insertion 161, the annular lips 31 and 131 match up. The clamp20 can then be used to connect the down tube 13 with the connection tube30.

FIGS. 15A-C illustrate another embodiment of the joint formed by theconnection tube 30 and the down tube 13 at the down tube junctionwherein FIG. 15A illustrates details of the connection tube 30, FIG. 15Billustrates more details of the down tube 13 and FIG. 15C illustratesthe down tube junction 74 with the connection tube 30 and the down tube13 coupled to each other. As shown in FIG. 15A, the connection tube 30has an annular lip portion 170 with a seating surface 171 at an endportion of the connection tube 30 that couples to the down tube 13. Asshown in FIG. 15B, the down tube 13 has a seating portion 172 with aseating surface 173 and an end portion 174 wherein the seating portionand the end portion have a diameter that is slightly smaller than theannular lip portion 170. When the connection tube 30 and down tube 13are fitted together, the end portion 174 slides into the connection tube30 and the annular lip 170 is pressed against and seated on the seatingportion 172 as shown in FIG. 15C so that the seating surfaces 171, 173abut up against each other. Obviously, the structures shown in theconnection tube 30 and the down tube 13 could be interchanged with eachother and would be within the scope of the invention.

The presence of the end portion 174 strengthens the structural integrityof the down tube junction 74 by providing extra support in the radialdirection, and contributes to maintaining the annular lip portion 170matched to the seating portion 172. Once the two tubes 30, 13 are fittedtogether, a clamp (not shown) such as that shown in FIG. 4A or 5A isclamped around the junction wherein the clamp presses the annular lipportion 170 and the seating portion 172 against each other. The clampalso applies a force directed radially inward (toward the center of thetube), and the end portion 174 helps counter this inward radial force.The forces of the clamp keep the annular lip portion and the seatingportion locked together so that any sliding between the annular lip 170and the seating portion 172 at the junction 74 is minimized. The downtube

1. A bicycle frame, comprising: a first frame section including a firsttube having a first junction portion having a seating portion and an endportion; a second frame section, the second frame section including asecond tube having a second junction portion having an annular lipportion; and a clamp that disengagably couples the first tube and thesecond tube to each other, wherein the end portion slides into thesecond tube and the annular lip portion abuts against the seatingportion when the first and second junction portions are coupled to eachother and the clamp holds the first junction portion and the secondjunction portion in fixed positions relative to each other.
 2. The frameof claim 1, wherein the clamp presses the annular lip portion againstthe seating portion and the end portion supports the annular lip portionwhen the clamp is tightened around the annular lip portion and theseating portion.
 3. The frame of claim 1, wherein the first tubecomprises a first portion of a down tube that is connected to a top tubeby a head tube, and the second tube comprises a connection tube that isconnected to a seat tube.
 4. The frame of claim 1, wherein the clampfurther comprises a groove into which the annular lip portion and theseating portion fit.
 5. The frame of claim 4, wherein the groove istapered so that the deeper portion of the groove is narrower compared tothe shallower portion of the groove.
 6. The frame of claim 1, whereinthe first tube and the second tube are made of different materials. 7.The frame of claim 1, wherein one of the first tube and the second tubeis made of carbon fiber and the other one of the first and the secondtubes is made of metal.
 8. The frame of claim 1, wherein the first framesection further comprises a third tube and the second frame sectionfurther comprises a fourth tube, wherein the third tube and the fourthtube are disengagably coupled with a post to form a second junction. 9.The frame of claim 8, wherein each of the third tube and the fourth tubecomprises a tightening mechanism so that the third tube and the fourthtube are disengagably coupled by being tightened around the post afterthe post is inserted through the third tube and the fourth tube.
 10. Ajunction for a connecting a first portion and a second portion of amember to each other, the junction comprising: a first member having afirst junction portion having a seating portion and an end portion; asecond member having a second junction portion having an annular lipportion; and wherein the end portion slides into the second member andsupports the annular lip portion and the annular lip portion abutsagainst the seating portion when the first and second junction portionsare coupled to each other.
 11. The junction of claim 10 furthercomprising a clamp that disengagably couples the first member and thesecond member to each other when the first and second junction portionsare coupled to each other wherein the clamp holds the first junctionportion and the second junction portion in fixed positions relative toeach other.
 12. The junction of claim 10, wherein the first memberfurther comprises a first bicycle frame portion and the second memberfurther comprises a second bicycle frame portion.
 13. The junction ofclaim 11, wherein the clamp presses the annular lip portion against theseating portion and the end portion supports the annular lip portionwhen the clamp is tightened around the annular lip portion and theseating portion.
 14. The junction of claim 1, wherein the first bicycleframe portion comprises a first portion of a down tube that is connectedto a top tube by a head tube and the second bicycle frame portionfurther comprises a connection tube that is connected to a seat tube.15. The junction of claim 13, wherein the clamp further comprises agroove into which the annular lip portion and the seating portion fit.16. The junction of claim 15, wherein the groove is tapered so that thedeeper portion of the groove is narrower compared to the shallowerportion of the groove.
 17. The junction of claim 1, wherein the firstmember and the second member are made of different materials.
 18. Thejunction of claim 12, wherein the first bicycle frame section furthercomprises a third tube and the second bicycle frame section furthercomprises a fourth tube, wherein the third tube and the fourth tube aredisengagably coupled with a post to form a second junction.
 19. Thejunction of claim 18, wherein each of the third tube and the fourth tubecomprises a tightening mechanism so that the third tube and the fourthtube are disengagably coupled by being tightened around the post afterthe post is inserted through the third tube and the fourth tube.